Fail-safe throttle control

ABSTRACT

The invention relates to a fail-safe throttle control mechanism which is positioned between an accelerator pedal of a motor vehicle engine incorporating a fuel injection system and includes a linkage assembly which extends from the accelerator pedal to the fuel injection control system and has combined therewith a sensing mechanism for disengaging the accelerator pedal from the fuel injection control system so that the engine of the motor vehicle can instantly return to an idle condition irrespective of any impairment in the control linkage or blockage of the accelerator pedal. There are disclosed various embodiments for achieving this fail-safe operation of fuel injection control mechanisms.

United States Patent 1191 MacMillan 1*Feb. 12, 1974 FAIL-SAFE THROTTLE CONTROL [76] Inventor: Charles W. MacMillan, 340020th St. Ct., Rocklsland, Ill.

[21] Appl. No.: 206,656

Related US. Application Data [63] Continuation-impart of Ser. Nos. 88,450, Nov. 10,-

1970, Pat. No. 3,626,919, and Ser. No. 153,330, June 15, 1971, Pat. No. 3,731,667.

123/198 D, 198 DB, 98, 108; 180/82, 82.1,

[56] References Cited UNITED STATES PATENTS 3,626,919 12/1971 MacMillan 123/198 DB Primary ExaminerAl Lawrence Smith Attorney, Agent, or FirmEdwin E. Greigg 5 7] ABSTRACT The invention relates to a fail-safe throttle control mechanism which is positioned between an accelerator pedal of a motor vehicle engine incorporating a fuel injection system and includes a linkage assembly which extends from the accelerator pedal to the fuel injection control system and has combined therewith a sensing mechanism for disengaging the accelerator pedal from the fuel injection control system so that the engine of the motor vehicle can instantly return to an idle condition irrespective of any impairment in the control linkage or blockage of the accelerator pedal. There are disclosed various embodiments for achieving this fail-safe operation of fuel injection control mechanisms.

9 Claims, 7 Drawing Figures SHEET 2 BF 2 9 'nunnn nnn.

ISI

Hill

FAIL-SAFE THROTTLE CONTROL gine of a motor vehicle which is controlled by a carburetor when the accelerator linkage becomes impaired, thus preventing proper operation because of jamming or freezing of the linkage, disconnection of parts, fail- Y ure of the accelerator linkage return spring, as well as most other forms of such difficulties.

As was disclosed in the earlier application Ser. No.

88,450 and was also true in application Ser. No. 153,330, it is of particular concern that the engine speed of the motor vehicle be returned to an idle condition when some impairment to the linkage operation occurs, for-it is vitally essential that the continued operation of the engine in present motor vehicles be maintained, since many of these vehicles depend upon power accessories, such as brakes and steering, that operate off the power-of the engine or vacuum of the manifold and which would otherwise be practically useless without the engine running.

As mentioned in the previous applications, the failsafe throttle control is indeed applicable to fuel injection racks of Diesel engines and, quite obviously, therefore the control mechanisms of all fuel injected engines whether Diesel or spark ignited. This application is intended to show application of the species of this invention to various fuel'injection control units as used in Diesel or gasoline powered engines.

Fuel injectors in most cases inject fuel under high pressure directly into the cylinder'at the correct time during the compression stroke to cause proper ignition in the Diesel or in time to be ignited in the spark ignition engine. Timing of injection is commonly controlled by a camshaft in the same manner as valve timing, as is well known in the art, and normally does not control the speed or load characteristics of the engine. in the fuel injected engine the speed is dependent upon the quantity of fuel injected and the amount of load applied, so that more fuel is needed when the load increases just to maintain the same speed (otherwise the speed will drop) or to increase the speed under a uniform load. The injector system therefore requires a metering system to provide precisely the right amount of fuel for the load conditions presented.

Various methods and combinations have been devised to meter and to distribute the fuel to each cylinder of an engine. There are three basic systems in use:

the individual pump system in which the fuel injector in each cylinder is the metering device and the high pressure pump, the distributor system in which a single pump provides the metering of the fuel and the high injection pressure, the fuel being routed through a distributor to the proper cylinder, and the common rail system wherein high pressure fuel is supplied from a single pump to all of the fuel injectors, the individual injector metering the quantity of fuel during injection.

All of the basic systems have a metering device which, in its most common form, is a helically grooved plunger within a housing with fixed inlet ports, which is axially moved a fixed distance by a cam which is gear driven fromthe crankshaft, and which meters the fuel by the angular relationship between the plunger and the housing. This angular relationship is most commonly achieved by utilizing a pinion gear attached to the plunger, this element engaging a rack" gear which is slidably fitted within the housing, so that when the rack is pushed or pulled, it changes the angular relationship between the plunger and housing and therefore the quantity of fuel metered. This rack is called a control rack or control rod. When multiple metering units are used, all of the racks are connected together, holding each plunger in precisely the same angular position, so that upon actuation each plunger meters exactly the same amount of fuel to its respective cylinder. Thus, it will be understood that when the rack is at one end of its stroke, the metering plunger is adjustedto provide maximum fuel allowing maximum speed, while when the rack is at the other end of its stroke, the plunger is adjusted to deliver no fuel, thus stopping the engine. Accordingly, it will be appreciated that by reciprocation of the rack between these extreme positions, the amount of fuel supplied is varied to provide speeds from idle to full speed. With the system disclosed herein and considered in its simplest form, with the accelerator linkage attached to the end of the control rod, control of the engine can be achieved in the same manner as in a gasoline engine which utilizes a carburetor.

As will be understood from a careful study of this application, it is not necessary, however, to have a direct mechanical connection to the control rack. Daimler Benz AG of Stuttgart-Unterturkheim, Germany, use, on their Mercedes. Benz automobile, a vacuumoperated governor between the manifold and the control rod and place a throttle plate within the intake manifold to control the amount of air fed to the engine, and thus vary the vacuum within the intake manifold, which, in turn, controls the position of the rack through a spring-loaded diaphragm. This provides not only the necessary movement of the control'rod, but constant speed governing as well.

Accordingly, the principal object of this invention is to incorporate, into the linkage system extending from the accelerator pedal of an internal combustion engine to the control rod or rack of a fuel injection system, a trigger mechanism which is capable of sensing an operators act of deceleration of a motor vehicle and compensation for any unknown impairment inthe linkage by instantly returning the control rack to idle position.

Another object of this invention is to provide for operation of the trigger mechanism by either mechanical, electrical and/or pneumatic means.

Still another object of thisinvention is to provide a fuel injection throttle control linkage system for use in motor vehicles which has incorporated therein a second trigger mechanism.

A still further object of this invention is to include in the electrical system for actuating the fuel injection Further objects and advantages will become apparent from a reading of the following specification taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1a and lb generally are side elevational views of the preferred embodiment of the invention showing the manner of connecting a fuel injection control rack to an accelerator pedal which includes dual pivot points;

FIG. 2 is an end elevational view of the trigger mechanism as viewed in the direction of the arrow adjacent to the line A-A in FIG. 1a;

FIG. 3 is a schematic side elevational view of a fuel injected engine showing one injector in a cylinder and one system of moving the control rack by rotation of a shaft which extends parallel to the axis of the engine;

FIG. 4 is a schematic side elevational view of a fourcylinder fuel injected engine showing the means of connecting the shaft which actuates the control rack to the fail-safe throttle control;

FIG. 5 is a schematic side elevational view of the preferred embodiment of the fail-safe throttle control in association with a pneumatic governor control; and

FIG. 6 is a schematic side elevational view of the invention utilizing a vacuum cylinder and a valve in place of the switch and solenoid of FIGS. 10 and lb.

Turning first to the view in FIG. lb there is shown a typical head-mounted fuel injector 150 commonly used on Diesel engines, and used on some spark ignition engines. Extending horizontally and outwardly towards the firewall of the vehicle is a control rack 151 engaging a gear 152, which when moved axially, rotates said gear and a housing 153. The injector piston 154 moves slidably in a fixed housing 155 upward and downward, being axially keyed and slidably fitted to the top of the rotatable housing 153 so that said piston turns with the housing 153 and can be angularly adjusted by said housing and therefore by the control rack 151. The injector piston 154 is pushed downward, through a fixed stroke determined by accelerator position, by a rocker arm, activated by a push rod and cam in exactly the same manner as the valves in an automobile engine, none of which is shown, since it is very well known to the art. The amount of fuel injected through an injection port 160 is controlled by a helix 156. The injection pressure, built up in a cavity 157 by injector piston 154 as it moves downward, is relieved when said helix passes a port 158. It should be obvious from the drawing that the angular position of injector piston 154 thus determines the volume of fuel injected. As the injector piston is rotated counterclockwise, the stroke becomes shorter before the helix intersects the port 158 and the fuel volume is small. When a slot 159 aligns with the port 158, no pressure can be built up, since port 158 is always open, and therefore no fuel is delivered. Accordingly, with such a condition, the engine will stop. The control rack 151 therefore controls the angular position of injector piston 154 and the volume of fuel injected, and, as discussed earlier, it therefore controls the speed of the engine.

The end of the control rack 151 is flattened and perforated to receive a pivot pin 161 to which is attached a clevis 162, which is rigidly attached to a push rod 163, the other end of which also terminates in a clevis. The rod 163 is pivotally attached to an upwardly extending car 164 of a pivotal lever 165, which, in my previous applications, was referred to as the throttle lever 18.

As is shown in FIG. 2, which generally corresponds to FIG. 2 in my copending application discussed hereinafter, the pivotal lever 165 includes integral, oppositely-offstanding flange portions, one of which is screwheaded and provided with a slow idle adjusting screw 20.

In a different way from my previous application the connecting linkage between 28 and solenoid 94 has been changed to include a new, non-rigid pull link 191 in place of rigid links 108 and 104. Should solenoid 94 have a tendency to stick, the use of non-rigid pull link 191 would prevent the throttle from being held open. The possibility of such a failure was'anticipated in my previous application Ser. No. 153,330, filed June 15, 1971, wherein FIG. 5 shows a resilient spring mechanism inserted into linkage 108 for just such purposes; however, the present construction is a greatly simplified and inexpensive form of achieving the same result.

The remainder of the mechanism shown in FIGS. 1a and 2 is identical in construction and operation to that of FIG. 1 of my previous application Ser. No. 153,330, filed June 15, 1971, wherein pivotal lever 165 assumes the identical function of the throttle lever of that application.

As described in my previous application Ser. No. 153,330, it should be clear that during normal operation of the motor vehicle the fail-safe system remains in a passive non-influential condition with the accelerator pedal serving to accelerate and decelerate the vehicle, by means of the elements described, to' maintain the electrical contacts 88 and of FIG. 1 out of contact, and the non-rigid pull link 191 and latch 22, best shown in FIG. 1, moving unrestrained with the linkage.

However, should various types of failure appear in the mechanism, which is required for normal operation of the vehicle, the electrical contacts are brought into engagement, as shown in FIG. 4 of my earlier application, this operation serving to retract the plunger of the solenoid into its housing, causing the non-rigid link 191 to pull the pin 30 forwardly, thereby rotating body 28 against spring 32 to withdraw the latch 22 from lever 26 so that the pivotal lever will instantly push the control rack to idle.

Referring now to FIG. 3 there is shown injector 150 mounted in cylinder head 166 so that control rack 151 moves horizontally and perpendicularly to the axis of the engine 167 and crankshaft 168 (shown in FIG. 4). At one end of said control rack is fitted a pivot pin 168, which is slidably fitted into slot 169 of lever 170, which, in turn, is rigidly mounted on shaft 171. Shaft 171 is disposed parallel to the axis of engine 167, pivotally mounted to supports (not shown) and rigidly affixed to a cylinder head 166, so that, as shaft 171 is rotated, control rack 151 is moved to the right or left. At one end of shaft 171 is rigidly mounted a control lever 172 having a pivot ball 173 extending horizontally therefrom. Pivotally mounted on pivot ball 173 is a socket 174 and a shaft 175, as is commonly used in modern day automotive carburetor linkages.

As shown in FIG. 4, shaft 175 extends downwardly terminating in a second ball socket 176 and pivotally attached to a ball 177, which is rigidly attached to a lever extension 178 which has been added to the pivotal lever 165.

Shown more clearly in H6. 4, the shaft 171 which extends forwardly along the upper side of the engine 167 past each of the fuel injectors 150, and at each of which are provided levers 170 to move the control rack 151 in precise alignment with all of the others, thus assuring the identical volume of fuel to each cylinder at its given speed setting.

It should be obvious that by rotating pivotal lever 165 clockwise, shaft 175 will push lever 172 upwardly, thereby rotating shaft 171 in such a manner as to move control rack 151 to the right, thus increasing the fuel volume and therefore the speed of the engine.

it should be obvious to those skilled in the art that the fail-safe system will operate, as in previous applications, by forcing lever 165 to return the control rack to idle, should the accelerator linkage become inoperative.

Referring at this time to FIG.5,- there is shown the Robert Bosch GMBl-l fuel injection system which includes an intake manifold 179 and within which is pivotally supported the throttle plate lever 181 by means of a shaft 182. The shaft 182 in this view performs the equivalent function of shaft 16 and to which is attached 151, a spring 187 being interposed between the diaphragm 186 and the inside right end wall of the housing 185. As shown, the chamber 188 to the left of vacuum diaphragm 186 communicates with atmosphere through opening 189.

it is believed to be apparent from the foregoing to those skilled in the art that this construction describes the well-known vacuum actuator.

At idle, the throttle plate is closed and the vacuum within the venturi 180 is high, therefore the vacuum within chamber 184 is high, causing diaphragm 186 to pull control rack to the right against the force of spring 187, thereby reducing the fuel flow to the engine. At other load and speed conditions the control rack position varies, depending upon the difference in pressure between chambers 184 and 188. At high engine load, the throttle-plate is wide open and the vacuum is low, allowing spring 187 to urge diaphragm 186, and thus control rack 151, to the left, providing maximum fuel flow. It can be seen that the control rack position is entirely controlled without a direct mechanical link to the accelerator pedal 52, and that throttle plate 181 performs in the same manner as throttle plate 14 of the conventional carburetor, thus the fail-safe throttle system would operate equally well when connected to throttle plate 181, in the same manner as in a conventional carburetor.

Pneumatic means may be substituted for the electrical means of actuating the safety trigger in the embodiments described in this and my previous application wherein a valve may be substituted for switch contacts 88 and 90 and a vacuum actuator for solenoid 94.

Referringnow to FIG. 6, there is shown the dual pivot acceleration mounting arrangement of my previous application with face 76 bearing against one end of rod 192 which is slidably fitted within guide 193 which is affixed to the firewall of the vehicle; the other end of rod 192 bearing against the face 194 of one arm of right angle lever 195 which is pivotally mounted through pin 196 to support 197 which is rigidly affixed to the body of the vehicle. The second arm of right angle lever 195 extends to the left and is urged downwardly by compression spring 198 which is disposed between its upper surface 199 and support surface 200 which is rigidly affixedto the body of the vehicle. The lower surface of the right angle lever arm bears against the actuating button 202 of a normally closed vacuum valve 203. One vacuum connection 204 of vacuum valve 203 communicates with the engine manifold vacuum and the other side of vacuum valve 203 communicates through tube 205 with vacuum actuator 206, the output shaft 207 being firmly connected to non-rigid pull link 191.

It will thus be apparent that the function of this arrangement of elements replaces the functions of solenoid 94 and contacts 88 and and their immediately associated elements. During normal operation of the vehicle the pull on cable 42 and/or the pedal pressure on pedal 52 force rod 192 against lever urging spring 198 against its support and allows actuating pin 202 to extend from the valve body 203 thus closing off the vacuum from the manifold to the vacuum actuator 206. Should the pull force in cable 42 be relaxed, however, due to the linkage sticking and the operator removes his foot from the pedal 52, the force against rod 192 is removed and spring 198 urges lever 195 and actuating pin 202 downward opening vacuum valve 203 causing vacuum to be applied to the vacuum actuator 206 pulling on the non-rigid pull link 191, thereby returning the throttle to idle as previously described.

In all Diesel applicationsa stop control is required to move the control rack to the stop position, where no fuel is delivered. This has not been shown in any of the schematic illustrations since it does not affect the basic operation of the fail-safe throttle control and can be accomplished in many ways that are well known to the art of Diesel control.

It should also be clear from the foregoing discussion that all of the other embodiments of my previous applications are applicable to fuel injection systems, as is the preferred embodiment, and that the embodiments described in thisapplication are applicable to carburetor controlled gasoline engines.

That which is claimed is:

1. A fall safe apparatus for controlling the speed of an engine comprising:

an engine speed control means,

a means for actuating said speed control means,

an accelerator pedal and means'operatively connecting said accelerator pedal and said actuator means, said connecting means including means for sensing failure of the accelerator pedal to return to a normal condition upon an attempt to decelerate,

means responsive to said sensing means for returning said actuating means to a position in which said engine speed control means causes said engine to run at idling speed, and

means effective to transmit force from said responsive means to said actuator means but ineffective to transmit force from said actuating means to said responsive means.

2. An apparatus as claimed in claim 1, wherein the force transmitted by the means which transmits force in one direction only is a tension force.

3. An apparatus as claimed in claim 2, wherein said means effective to transmit force in one direction only comprises an elongated flexible member.

4. An apparatus as claimed in claim 1, wherein said engine is an internal combustion engine of the fuel injection type and said speed control means includes rack and pinion means controlling the position of injector pistons.

5. A fail safe apparatus for controlling the speed of an engine comprising:

an engine speed control means,

a means for actuating said speed control means,

an accelerator pedal and means operatively connecting said accelerator pedal and said actuator means, said connecting means including means for sensing failure of the accelerator pedal to return to a normal condition upon an attempt to decelerate, and

means responsive to said sensing means for returning said actuating means to a position in which said engine speed control means causes said engine to run at idling speed,

said responsive means comprising a valve responsive to said sensing means, said valve controlling the application of vacuum to a cylinder and piston means.

6. An apparatus as claimed in claim 5 comprising means effective to transmit force from said responsive means to said actuator means but ineffective to transmit force from said actuating means to said responsive means.

7. An apparatus as claimed in claim 6 wherein the force transmitted by the means which transmits force in one direction only is a tension force.

8. An apparatus as claimed in claim 7, wherein said means effective to transmit force in one direction only comprises an elongated flexible member.

9. An apparatus as claimed in claim 8, wherein said engine is an internal combustion engine of the fuel injection type and speed control means includes rack and pinion means controlling the position of injector pistons. 

1. A fail safe apparatus for controlling the speed of an engine comprising: an engine speed control means, a means for actuating said speed control means, an accelerator pedal and means operatively connecting said accelerator pedal and said actuator means, said connecting means including means for sensing failure of the accelerator pedal to return to a normal condition upon an attempt to decelerate, means responsive to said sensing means for returning said actuating means to a position in which said engine speed control means causes said engine to run at idling speed, and means effective to transmit force from said responsive means to said actuator means but ineffective to transmit force from said actuating means to said responsive means.
 2. An apparatus as claimed in claim 1, wherein the force transmitted by the means which transmits force in one direction only is a tension force.
 3. An apparatus as claimed in claim 2, wherein said means effective to transmit force in one direction only comprises an elongated flexible member.
 4. An apparatus as claimed in claim 1, wherein said engine is an internal combustion engine of the fuel injection type and said speed control means includes rack and pinion means controlling the position of injector pistons.
 5. A fail safe apparatus for controlling the speed of an engine comprising: an engine speed control means, a means for actuating said speed control means, an accelerator pedal and means operatively connecting said accelerator pedal and said actuator means, said connecting means including means for sensing failure of the accelerator pedal to return to a normal condition upon an attempt to decelerate, and means responsive to said sensing means for returning said actuating means to a position in which said engine speed control means causes said engine to run at idling speed, said responsive means comprising a valve responsive to said sensing means, said valve controlling the application of vacuum to a cylinder and piston means.
 6. An apparatus as claimed in claim 5 comprising means effective to transmit force from said responsive means to said actuator means but ineffective to transmit force from said actuating means to said responsive means.
 7. An apparatus as claimed in claim 6 wherein the force transmitted by the means which transmits force in one direction only is a tension force.
 8. An apparatus as claimed in claim 7, wherein said means effective to transmit force in one direction only comprises an elongated flexible member.
 9. An apparatus as claimed in claim 8, wherein said engine is an internal combustion engine of the fuel injection type and speed control means includes rack and pinion means controlling the position of injector pistons. 